OLED Sub-Pixel Electrode Thickness for Brightness Uniformity
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Solution Overview
Problem
Display devices with sub-pixels of varying sizes due to incorporation of features like pinch holes lead to brightness deviations and non-uniformity, affecting the performance and lifetime of organic light-emitting diodes.
Innovation Solution
The display device incorporates sub-pixels with differently sized electrodes based on the thickness of their conductive layers, with a pixel-defining layer defining the openings to expose portions of the electrodes, ensuring uniform brightness and reducing the deterioration of light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sub-pixels are designed with different sizes to accommodate pinch holes or other integrated components, then device functionality and adaptability are improved, but brightness uniformity and visual quality deteriorate
Solution Approach 1:
The patent applies local quality by adjusting the electrode thickness specifically in regions where sub-pixel size variation occurs. Instead of making all sub-pixels uniform in size (which would limit adaptability), the invention modifies the local electrode structure in affected areas to compensate for size differences, thereby maintaining brightness uniformity while allowing functional adaptability.
Solution Approach 2:
The patent changes the physical parameter of electrode thickness to compensate for sub-pixel size variations. By varying the electrode thickness parameter in response to sub-pixel area differences, the invention maintains consistent light emission intensity across sub-pixels of different sizes, resolving the brightness uniformity issue while preserving design flexibility.
2Adaptability or versatility
If sub-pixel sizes are varied to integrate components like cameras and sensors, then device versatility is improved, but brightness deviation between sub-pixels worsens
Solution Approach 1:
The patent implements local quality by applying different electrode thicknesses to different sub-pixel regions. Sub-pixels that are smaller due to integrated components receive thicker electrodes to compensate for reduced light emission area, while larger sub-pixels have thinner electrodes, thereby maintaining consistent brightness across the display.
Solution Approach 2:
The patent employs asymmetry by deliberately creating non-uniform electrode thicknesses corresponding to non-uniform sub-pixel sizes. This asymmetric design allows each sub-pixel to be optimized for its specific area, compensating for size variations caused by integrated components and ensuring uniform brightness output.
3Illumination intensity
If electrode thickness is increased to compensate for smaller sub-pixel areas, then brightness uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the electrode structure into multiple thickness zones corresponding to different sub-pixel regions. This segmentation allows precise control of electrode thickness in each area to achieve brightness uniformity while maintaining a systematic manufacturing approach that can be implemented through patterned deposition processes.
Data Source
AI summary
A display device includes: a substrate including a display area and a non-display area; and a plurality of sub-pixels arranged in the display area and including portions of an electrode disposed over the display area. The plurality of sub-pixels includes a first sub-pixel and a second sub-pixel to emit light of the same color, a first portion of the electrode of the first sub-pixel has a thickness different from a thickness of a second portion of the electrode of the second sub-pixel, and the first sub-pixel has a size different from a size of the second sub-pixel.